Electrical control apparatus



March 25, 1952 E. D. MEAD ETAL ELECTRICAL CONTROL APPARATUS 7 Sheets-Sheet 1 Filed Feb. 15, 1945 FIG.

March 25, 1952 E. D. MEAD ETAL 2,590,263

ELECTRICAL CONTROL APPARATUS Filed Feb. 13; 1945 7 Sheets-Sheet 2 n 2 (C9) a FIG 2 & N

' 5.0. MEAD INVENTORSOSA. MESCH "d Q CEWQ A TTORNEV March 25, 1952 E. D. MEAD ETAL ELECTRICAL CONTROL APPARATUS '7 Sheets-Sheet 5 Filed Feb. 15, 1945 ATTORNEY March 25, 1952 E. 0,. MEAD ETAL 2,590,263

ELECTRICAL CONTROL APPARATUS I Filed Feb. 15, 1945 7 Sheefl'fs-Sheef. 4

FIG. 8

TYPE A E. 0.114540 nvvmrons as A MESCH y @(acW A TTORNEY March 25, 1952 E. D. MEAD ETAL 2,590,263

ELECTRICAL CONTROL APPARATUS I Filed Feb. 15, 1945 7 Sheets-Sheet 5 F IG. .9

TYPE A FIG. /0

TYPE B E. 0. MEAD MEMO 0. $.A.ME$CH 2/2 205 BY @figMM ATTORNEY March 25, 1952 E. 0. MEAD ETAL 2,590,263

ELECTRICAL CONTROL APPARATUS Filed Feb. 13, 1945 '7 Sheets-Sheet e TYPE E TYPE 0 6.9 m 5g; 23 23/ L d;j /6'5 50.44010 WVENTORS O.S.A.MESCH ATTORNEY March 25, 1952 E. D. MEAD ETAL 2,590,263

ELECTRICAL CONTROL APPARATUS Filed Feb. 13, 1945 '7 Sheets-Sheet 7 FIG/l6 E. D.MEAD WVENTORS-QSA. MESCH A TTOP/VE V Patented Mar. 25, 1952 UNITED STATES PATENT OFFICE 2,590,263 ELECTRICAL CONTROL APPARATUS Edward D. Mea d,' Caldwell, N. J and Orwar S. A.

Mesch, St. Albans, N. Y., assignors to Bell Telephone Laboratories Incorporated, New York, N. Y., a corporation of New York Application February 13, 1945, Serial No. 577,632

, 3 Claims. 1

This invention relates to electrical control apparatus and more particularly to electrical control apparatus comprising a removable control panel on which turnable control knobs are provided to facilitate operation of electrical devices in the control apparatus.

The object of the invention is to provide improved control panel and knob means for electrical control apparatus.

A feature of the invention resides in the control panel on which the control knobs are mounted.

Another feature resides in the control knobs in which means are provided to render the knobs effective to turn shafts and ineffective to turn the shafts.

Another feature resides in a mechanical brake means for the control knob.

Another feature resides in a coupling mounted on part of the control apparatus and engaging part of a control knob when the control panel is mounted in normal position.

In the drawings:

Fig. l is a front elevation of the electrical control apparatus;

Figs. 2 and 3 are respectively a left side elevation and a right side elevation of the electrical control apparatus;

Fig. 4 is a view, in section, of one of the forms of control knobs in engagement with a coupling;

Fig. 5 corresponds to Fig. 4 but with parts of the control knob in condition to cooperate in turning the coupling;

Fig. 6 is a top view of the control knob shown in Figs. 4 and 5 and with part of the structure broken away to disclose other parts;

Fig. 7 is a top view of another form of control knob and in which a crank is provided to facilitate turning the knob;

Fig. 8 is a view, in vertical section, of the control knob shown in Fig. 7 and shows the brake and a switch controlled by means of the brake;

Fig. 9 corresponds to Fig. 8 but with the crank and brake moved to different positions;

Fig. 10 is a view, partly in section, of another form of control knob and provided with an electric switch means;

Fig. 11 is a view, partly in section, of another form of control knob;

Fig. 12 is a view, in section, of another form of control knob;

Fig. 13 is an end view of a coupling;

Fig. 14 is a side view, in section, of the coupling shown in Fig. 13;

Fig. 15 is a view of the coupling shown in Fig. 13 but with a clutch plate removed;

Fig. 16 is a side elevation of the coupling parts shown in Fig. 15 but turned 90 degreesrelative to that figure;

Fig. 17 is a face view of a clutch disc to engage the clutch plate of the coupling parts shown in Figs. 13 and 14; and

Fig. 18 is a side view, in section, of the clutch disc shown in Fig. 17.

The electrical control apparatus of this invention has been found useful in gun director apparatus and is illustrated in Figs. 1, 2 and 3 as included in a computer, the function of which is to determine how guns on a ship must be aimed so that a projectile or projectiles will reach a target.

The computer shown in Figs. 1, 2 and 3 comprises a casing 20 having a-lbase 2!, a left side wall 22, a right side wall .23, a back wall 24, a front frame 25 and removable control panels 25, 21 28 and 29. The control panels 26, 21, 28 and 29 are removably mounted on the front of the casing 20 by means of bolts-or other suitable fastening means 30 which extend through apertured recesses 3| in the control panels and intoother portions of the casing 20. The control panels are equipped with handles 31 to facilitate handling the control panels when the control panels are being removed from or applied to the casing 20.

The control panels 26, 21, 28 and 29 are apertured at required points to accommodate parts of control members and so that dials and signal lights of electrical devices mounted in the casing 20 may be seen. On the computer shown in Fig. 1 the dials 32 indicate elevation, the dials 33 range, the dials 34 the relative positions of the ship and target and the dials 35 the bearing. Jewel lenses 3!; are mounted on the control panels to cover signal lights located within the easing 20. Indicators of other electrical instruments may be seen through the apertures 38, 39, 40, 4|, 42, 43, 44, 45, 46, 41, 48, 49, 50, 5|, 52 53, 54, 55 and 56. The left side wall 22 of the casing 20 is apertured to accommodate parts of control members and apertures are provided at 51, 58, 59 and 60 in order that indicators of electrical instruments located within the casing in line with these apertures may be seen. The right side wall 23 is apertured to accommodate a control member and is apertured at 6| for observance of an indicator. Terminals 62, 63, 54 and for conductor wires are mounted on the right side wall 23.

For manual control of some of the electrical devices supported in the casing 20 rotatable control members comprising knob devices are provided. Some of the knob devices are supported on the control panels 26, 21, 28 and 29 so that when it becomes necessary or advisable to remove the control panels from the casing 20 the control knobs will not have to be first removed but will simply come away with the control panels. The

control knob devices are made in several different forms and each form will be subsequently described. Each control knob device however comprises a handhold member, normally free to rtate without affecting apparatus in the casing, and a plunger device nested within the handhold member and operable to make the handhold member of the knob device effective to turn a shaft located within the casing 29. Some of the knob devices are equipped with a crank and handle to facilitate turning the shaft and some are provided with brake means to prevent undue turning of parts. In some cases switch contacts are arranged for operation by means of the knob devices.

Five different types of control knob devices are employed in the computer shown in Figs. 1, 2 and 3 and the types are identified as A, B, C, D and E1.

The type C control knob device 66 is shown in Figs. 4, 5 and 6 and the structure of this type of control knob device follows, in general, the pattern of the other control knob devices.

- The control knob device 96 shown in Figs. 4, 5 and 6 comprises an apertured body 61 and a knob 68. The body 61 is mounted on an apertured panel 69 and is secured thereto by bolts 19 or other suitable fastening means. The panel 69 may be one of the control panels 26, 27, 28 and 29 and the bolts I9 may enter a ring II. Secured within the body 61 and extending upwardly therefrom is a tubular bearing member 12 which is which is movable lengthwise in the tubular shaft 83. The bar 98 is provided with embossings I99 to selectively enter the indentations 99 in the plate 8'! when the plunger 99 is moved lengthwise in the shaft 83 to bring the bar 98 into engagement with the plate 81. The plunger 99 is 1 equipped with an end bearing I9I comprising a made threaded at the upper end 13 and provided with spaced outer bearing surfaces 14 and I5, an outer flange I6 and an inwardly extending end flange I1. The knob 68 is centrally apertured and comprises a handhold portion 18 and a neck portion I9. A sleeve bearing 89 is located within the neck portion 19 and frictionally engages the bearing surfaces 14 and I5 of the bearing member 12. The bearing 89 is secured against withdrawal from the knob 98 and may have end portions staked or spun over against portions of the knob 68 as indicated at 8|. One end of the bearing 89 is. in engagement with the flange I6 and the other end is in engagement with one of the locknuts 82 secured to the threaded end 73 of the tubular bearing member 12. A tubular shaft 83 extends through the tubular bearing member Hand is enlarged at spaced points to provide bearing surfaces 84 and 85 in frictional engagement with the inner surface of the tubular bearing member 12. The shaft 83 has a reduced upper end portion 89 on which is mounted an apertured circular plate 87. The upper end of the shaft 83 is staked or spun over at 88 in a recess 89 formed in the upper surface of the plate 87 to 'hold the plate 81 securely fastened to the shaft 83. Spaced indentations 99 are provided in the upper surface of the plate 81, the indentations 99 being of generally hemispherical form and arranged in an annular row concentric with the shaft 83. The indentations 99 may terminate at their lower ends in apertures 9I formed in the plate 81. The handhold portion 18 of the knob 68 is recessed at 92 to accommodate the upper portions of the bearing 12 and the shaft 83, and to accommodate the locknut 82 and the plate 81. The upper end of the recess 92 opens into a recess 93 which extends to the top of the handhold portion 18 of the knob 68. The recess 93 is reduced in diameter at its lower end to provide a ledge 99 which is cut away at diametrically spaced points to provide keyways 95-95 to receive the ends 96 and 91 of a bar 98. The bar 98 is secured to the upper end of a plunger 99 stem I92 terminating at one end in an enlarged end portion I93 having a rounded bearing surface I94. The stem I92 is accommodated in a recess I95 formed in the plunger 99 in which it is retained by means of a bearing-button I96 supported on one end of a spring I91, theother end of the spring I91 being in engagement with a rod portion I98 of a clutch device I99. The rod portion I98 extends into the tubular shaft 83 and is secured in place by means of a pin II9 which extends transversely through the rod portion I98, the lower end of the tubular shaft 83 and a ring III. The lower end of the rod portion I98 terminates in a plate portion I I2 on the lower face of which is a diametrically extending bar portion I I3 having bevelled edge portions I I4. The bar portion H3 is dimensioned to fit into a corresponding recess H5 in a coupling device II8 which may be secured to a rotatable shaft II! by means of a pin H8 or other suitable fastening means. The shaft II'I may be part of a potentiometer or other device to be operated by means of the control knob device 96. The structure of the coupling device I It will be subsequently described since an understanding of the operation of the control knob device 66 may be had without consideration of the structure and arrangement of the coupling device I I6.

When the control knob device 66 is supported on the panel 69 and the parts are in the positions shown in Fig. 4 the knob 68 may be rotated without causing rotation of the shaft 1. In this case the bearing 89 turns on the bearing surfaces 14 and I5, the bar 98 turns with the knob 68, the plunger 99 rotates with the bar 98 and the end bearing I9I rotates without transmitting any rotational movements to the rod portion I98 of the clutch device I99. To rotate the rod portion I98 of the clutch device I99 by means of the knob 68 the embossing I99 on the bar 98 must be brought into the indentations 99 in the plate 81 and the knob 98 must be turned While the embossings I99 are in the indentations 99. To bring the embossings I99 into the indentations 99 the plunger 99 may be pressed inwardly of the knob 68 by applying a suitable pressure to a disc II9 which is secured to the top of the bar 98 by rivets or other suitable fastening means I29.

When the plate portion I I2 of the control knob device 66 is to turned by operation of the knob 98 the plunger 99 is pressed within the knob 98 and against the action of the spring I91 until the embossings I99 are within the recesses 99 as shown in Fig. 5. In this case when the knob 98 is turned and the bar 98 is rotated the plate 81 is rotated by means of the bar 98. Since the plate 81 is secured to the tubular shaft 83 the shaft 83 is rotated and causes rotation of the plate II2. Rotations of the plate II2 are transmitted to the coupling device IIB since the bar portion H3 is engaged in the recess H5 in the coupling device II6. Rotation of the coupling device H6 causes rotation of the shaft Ill. The spring pressure developed in the spring I91 constantly endeavors to move the bar 98 out of engagement with the plate 81. Pressure must therefore be maintained on the disc II9 whenever the shaft III is being turned by means of the knob device 66. If the pressure on the disc I I9 is relaxed the embossings I will come out of the indentations 90 and there will be no driving connection between the bar 98 and the plate 81 and hence no turning of the plate H2 and the shaft H1.

The natural way for an operator to operate the control knob device 66 to turn the shaft H1 is to press the plunger 99 inwardly of the knob 68 by thumb pressure applied to the disc H9 and maintaining the thumb pressure while the knob 68 is turned to cause turning of the shaft H1. Unless the shaft H1 is rather freely turnable it will be difficult to keep the plunger 99 pressed inwardly of the knob 63 since even a slight increase in load on the shaft II! will be felt in the disc I I9 and a relatively large increase in the load on the shaft I I1 and continued efforts to turn the knob 68 will result in the embossings I00 riding out of the indentations 90 in the plate 81.

The coupling H6 serves as a mechanical connection between the control knob device 66 and the shaft Ill. The coupling H6 is attached to the shaft Ill and the only connection between the coupling H6 and the control knob device 66 is by virtue of the engagement of the bar portion H3 on the plate H2 with the corresponding recess in the coupling H6. The control knob device 66 is mounted on the panel 69 and will come away with the panel 69 when the panel 69 is removed from the casing 20. The shaft H1 and the coupling H6 are located at some distance from the panel 69 and remain in the casing. The coupling H6 shown in Figs. 4 and 5 comprises a body I2I having an apertured base portion I22 and an end portion I23 in which the recess H5 is formed. The base portion I22 is apertured to accommodate the boss portion I24 of a flange I25. The flange I25 operates in a slot formed in the body I2I and may be moved lengthwise of the body I2I against the action of a spring I26, one end of which rests in a recess I2I formed in the flange I25, the other end of the spring I26 being in engagement with the inner face of the end portion I23 of the body I2 I. When the panel 59 with the knob device 66 supported thereon is mounted on the casing 26 the plate H2 engages the end portion I23 of the body I2I of the coupling H6. The body I2! is normally thrust by means of the spring I26 rather close to the normal position of the panel 69 and so that when the panel 69 is finally bolted in required position the body I2l of the coupling device H6 will be pressed lengthwise of the boss portion I24 of the flange I25 and against the action of the spring I26. The spring I26 serves to maintain the body I2I in engagement with the plate H2 and so that the bar portion H3 will rest in the recess H5. The coupling H6 will automatically adjust itself to slight differences in spacing of the shaft H! from the normal position of the panel 69.

It will be seen, therefore, that a number of shafts II'I may be mounted in the casing to the rear of the normal position of the panel 69, that knob devices. of the general pattern of the knob device 66 may be mounted on the panel 69 to provide means for operating the shafts II! and that when the shafts II! are equipped with the couplings H5 the couplings H6 will automatically adjust themselves to compensate for slight differences in the spacing of the shafts III from the normal position of the panel 69. Under ordinary conditions the knob '68 may be freely turned without turning 6 the shaft I IT. The only way in which the shaft H1 may be turned by means of the knob 68 is by pressing the disc H9 inwardly of the knob 68 to bring the bar 93 into engagement with the plate 81 so that the embossings I60 engage in the indentations 90 and then holding the parts in this condition while the knob 69 is turned.

The embossings I06 are made well rounded, the indentations 90 are made relatively shallow and the spring I0! is constantly endeavoring to keep the bar 93 spaced from the plate 81. Any appreciable increase in load on the shaft III tending to retard or stop rotations of the shaft I I7 will be reflected to the bar 98. The increase in load will be felt by the operator of the knob 66 and if the load is increased beyond a predetermined limit and turning of the knob 68 is continued the embossings I00 will act as cams to move the bar 98 to such position that the bar 98 is not in driving engagement with the plate 61. The torque applied to the shaft 83 is ob tained by turning the knob 68 but the maintaining of the drive connection between the bar 93 and the plate 8'! is dependent upon the pressure maintained on the disc H9.

The type A control knob device 23 is shown in Figs. 7, 8 and 9 and comprises a body I29, a knob I30, a crank I3I, a shaft I32 and a disc I33. The body I29 is mounted on the panel 66 by bolts or other suitable fastening means I34 and supports a tubular bearing I35 which extends longitudinally within and beyond the body I29. The bearing I35 is flanged at I36, male threaded at I31 and provided with spaced outer bearing surfaces I38. The knob I is provided with a sleeve bearing I39 which is secured to the knob I30 and frictionally engages the bearing surfaces I38 and the flange I36. Locknuts I49 are mounted on the bearing I at I31 to retain the knob I30 on the bearing I35. Extending longitudinally within the bearing I35 is a bushing I4I having a flange I42 on one end and an inwardly thickened portion I43 on the other end and in which a noncircular aperture I44 is provided. The knob I30 is recessed at I45 to receive a plug I45 which extends over the flange I42 and is secured by suitable fastening means I41 to the knob I39. The plug I46 and the flange I42 are secured against relative rotation and screws I48 may be provided for this purpose. The crank I3I is mounted on a shaft I49 extending diametrically of the plug I46 and across a slot I50 formed in the plug I46. End bearings I5I are provided in the plug I46 to receive ends of the shaft I49. The crank I3I is constructed and arranged so that it may be used to facilitate turning the knob I30 and to longitudinally move the shaft I 32 in one direction in the bushing MI. The shaft I32 has a non-circular enlarged portion I52 fitted into the aperture I44 in the bushing MI and is operated in the manner of a plunger within the bushing I4I. A spring I53 disposed within the bushing I M and engaging the end portion I43 and a cap I54 on the shaft I32 serves to return the shaft I32 to normal position. The cap I54 extends above the flange I42 and is attached to the shaft I32 in any suitable manner. The lower end of the shaft I32 extends below the bushing MI and carries a cup-shaped member I55 which has an apertured boss portion I56 extending upwardly from the inverted cup portion I5! and within the tubular bearing I35. The boss portion I56 is secured by means of a pin I58 to the shaft I32 and accommodates a stem portion I59 of the plate I33, the stem portion I59 being secured to the boss portion I56 by a pin I60 or other suitable fastening means. The plate I33 is apertured at spaced points to provide a circular row of apertures I6I which are enlarged at one end to provide generally hemispherical indentations I62. The plate I33 forms part of a clutch device I63 and the cup-shaped member I55 forms part of a brake device I64.

The clutch device I63 comprises the plate I33 and a coupling I65, one portion of which is attached to a rotatable shaft I66 and which is to be turned by means of the knob device I28. The coupling I65 comprises a body I61 having an apertured base portion I68 and an end plate I69. Embossings I are provided on the end plate I69 to engage in the indentations I62 in the plate I33. The base portion I68 is apertured to accommodate the boss portion I1 I of a flange I12. A spring I13 is disposed between the inner face of the end plate I69 and the flange I12 to urge the body I61 and the end plate I69 in the direction of the plate I33, the extent of movement in this direction being limited by the flange I12 which is secured to the shaft I66.

When the shaft IE6 is to be rotated by means of the knob device I28 the crank I3I is swung across the knob I30 from the position shown in Figs. 7 and 8 to the position shown in Fig. 9. In doing this the shaft I32 is pressed inwardly of the knob I30 by means of the crank I3I which has an enlarged portion I14 eccentric with the shaft I49 and operating as a cam to force the shaft I32 inwardly of the knob I30 and longitudinally of the bushing I4I against the action of the spring I53. Movement of the crank I3I to the position shown in Fig. 9 brings the plate I33 Into engagement with the end plate I69 of the coupling I65. In this position the embossings I10 on the end plate I69 engage in the indentations I62 in the plate I33 and so that when the plate I33 is rotated the coupling I65 will be rotated to rotate the shaft I66. The pressure of the spring I13 is somewhat increased in bringing the plate I33 into engagement with the end portion I69 of the coupling I65 and this pressure is sufficient to keep the end portion I69 in engagement with the plate I33 while the plate I33 is being rotated unless the load on the shaft I66 is greater than a predetermined limit. If the load on the shaft I66 is greater than the predetermined limit or becomes such While the plate I33 is being rotated the embossings I1 will ride out of the indentations I62 so that the coupling I65 will not be rotated by the rotating movement of the plate I33. The enlarged portion I14 of the crank I3I is provided with a flat surface at I15 to engage the top of the cap I 54 when the crank I3I is in the position shown in Fig. 9. The fiatto-fiat engagement of these parts prevents the pressure of the spring I53 from moving the crank I3I from the position shown in Fig. 9.

When the crank I3I is in the position shown in Fig. 9 the crank I3I may be operated in the usual manner of a crank to rotate the knob I30, the cranking action applied to the crank I3I being transmitted to the knob I30 by way of the shaft I49 which extends crosswise of the crank I3I and diametrically of the plug I46. Rotations of the knob I30 are transmitted to the bushing I4I since the plug I46 is secured to the flange I42 of the bushing MI. The bushing I4I rotates within the bearing I35 and since the enlarged portion I52 on the shaft I32 is non-circular and fits the noncircular aperture I44 in the bushing MI and does not come out of the bushing I the rotations of the bushing I4I are transmitted to the shaft I32. The cup-shaped member I55 is secured to the shaft I32 and the plate I33 is secured to the cupshaped member I55. Rotations of the shaft I32 are therefore transmitted to the plate I33 by way of the cup-shaped member I55. The handle I18 of the crank I3I is normally left in the positions shown in Figs. '7 and 8 and so that the handle I16 extends into a notch I11 formed in the knob I30. The plug I46 is provided with a step I18 in the slot I50 to provide a rest for the arm I19 of the crank I3I when the crank I3I is in the position shown in Figs. '1 and 8. Diametrically across from the notch I11 a notch I is provided in the knob I30 to accommodate the arm I19 of the crank I3I when the crank I3I is in the position shown in Fig. 9. The slot I50 in the plug I46 is in alignment with slots I8I and I82 formed in the knob I39.

The brake device I64 comprises a support I83, 9. set of spaced posts I84 extending from the support I83 and a brake member I85. The brake member I85 is movably mounted on the posts I84 and is provided with apertures I86 at spaced points to accommodate the posts I84. The posts I84 are internally threaded to receive screws I81 which are adjustably mounted in the ends of the posts I84. Springs I88 and Washers I89 are supported on the shanks of the screws I81 and the springs and washers are disposed between the heads I90 of the screws I81 and the brake member I85, the springs I88 serving to urge the brake member I85 toward the cup-shaped member I55. The rim of the cup-shaped member I55 is externally bevelled at I9I to meet and frictionally engage an internally bevelled boss I92 on the brake member I85. The support I83 may be mounted on bolts I93 extending from a wall I94 contained within or forming part of the casing 20. The brake member I 85 may be adjusted relative to the cup-shaped member I 55 by manipulation of the screws I81 and may be normally set to be just clear of engagement with the cupshaped member I55 or may be set as shown in Fig. 8 to lightly engage the cup-shaped member I55 when the crank I3I is in the position shown in Fig. 8. When the crank I3I is moved to the position shown in Fig. 9 the cup-shaped member I55 is moved against the brake member I85 and to a suilcient extent to materially increase the pressure of the springs I88 to provide more braking action between the cup-shaped member I55 and the brake member I85. The braking action obtained should be sufficient to prevent undue turning of the shaft I66 by inertia of the parts forming a load on the shaft I66 or forming parts of the knob device I28. By suitable adjustment of the screws I81 to control the pressure of the springs I88 a predetermined pressure of the brake member I85 against the cup-shaped member I55 may be obtained.

In some cases the control knob apparatus is associated with an electric switch in order that the switch may be operated to a predetermined condition when the knob device I28 is conditioned to control the shaft I66. For this purpose a switch I95 is provided. The switch I95 may comprise a pile-up I96 of spring contacts with a pin I91 arranged in the path of movement of the brake member I85 and operable to move contacts in the pile-up I96 when the brake member I85 is moved. In Fig. 8 the pin I91 is pressed by the brake member I85 to make contact I98 engage contact I99. In Fig. 9 the knob device I28 has been conditioned to control the shaft I66, the brake member I85 has been moved by means of the cup-shaped member I55 away from the switch I95 and contact I98 has moved under its own spring tension away from contact I99 and into engagement with contact 200.

The type B control knob device 20l shown in Fig. is constructed along the general lines of the type A control knob device I28 shown in Fig. 9. Any parts in the type 13 control knob device that are identical with parts in the type A control knob device are identified in Fig. 10 by the same numerals as are used to identify the parts in Fig. 9.

In the type B control knob device 20I a cupshaped member 202 is supported on the shaft I32 in place of the cup-shaped member I55 employed in the type A. The cup-shaped member 202 carries a switch operating member 203 which is annular in form and has an annular wall portion 204 terminating in a shoulder 205. A switch device 206 comprising a pile-up 201 of spring contacts and an operating arm 208 is supported on a support 209 in position to be operated by means of the switch operating member 205. The operating arm 208 is mechanically connected to the contact spring 2I0 by means of a pin 2H and supports a wheel '2I2 which rides on the shoulder 205. When the arm I19 is swung across the knob I30 from the position shown in Fig. 10 to a diametrically opposite position and so that the flat surface I is in engagement with the cap I54 the shaft I32 is moved downward from the position shown in Fig. 10 to carry the cupshaped member 202 and the switch operating member 203 downward. The downward movement of the switch operating member 203 is transmitted to the arm 208 through the shoulder 205 and the wheel 2I2. Downward movement of the arm 208 results in the movement of spring contact 2I0 from engagement with spring contact 2I3 and engagment of contact 2I0 with contact 2I4. When the knob I30 is rotated the switch operating member 203 rotates and the wheel 2I2 rides on the shoulder 205. In the type B knob device I the arm I19 carries a button 2 I5 on one end in place of the handle I16 in the type A. The button 2I5 may be used in some measure to facilitate turning the knob I33 or may be employed as a signal to indicate the condition of the knob control device. In some cases the button 2I5 is colored red to serve as a danger signal when it is moved from the position shown in Fig. 10 diametrically across the knob device I and the knob device is in condition to turnthe coupling I65 and the switch 206 is operated to close contact 2I0 against contact 2 I4.

The type E control knob device 2H5 shown in Fig. 11 is like the type A control knob device I28 shown in Fig. 8 with the exception, however, that in the type E the brake device I64 of type A is not included and a modified cup-shaped member is employed. The cup-shaped member 2II is bevelled on the inner surface of the rim as shown at 2I8 to more readily guide the coupling device I65 into the space defined bythe cup-shaped member 2I1 when the panel 69 with the knob device '2I6 is being applied to the easing 20.

The type D control knob device 2I9 shown in Fig. 12 follows in general the pattern of the type C control knob device 66 shown in Figs. 4, 5 and 6. The type D however is somewhat simpler inconstruction than the type 0. Certain parts in the type D control knob device are duplicates of corresponding parts in the type C control knob device. Since the structures of these parts have already been described in the specification no further description of the parts is necessary to an understanding of the invention and the parts are simply identified in Fig. 12 with the same numerals as in Figs. 4, 5 and 6. Secured within the body 61 and extending upwardly therefrom is a tubularbearing member 220 which follows the structure of the bearing member 12 in the type C control knob device with the exception that in the bearing member 220 the lower end does not have the inwardly extending flange 11. Extending longitudinally within the bearing member 220 is a bushing 22I having a flange 222 on one end and an inwardly thickened portion 223 on the other end and in which a non-circular aperture 224 is provided. The flange 222 rests on top of the bearing 220 and the bushing 22I may be rotated within the bearing 220. A shaft 225 is supported in the bushing 22 I and is provided with a non-circular enlarged portion 226 to fit the non-circular aperture 224 in the bushing 22I. The shaft 225 is operable in the manner of a plunger in the bushing 22I against the action of a spring 221 and carries on its lower end an apertured plug 228 which is secured to the shaft 225 by a pin 229 or other suitable fastening means. Secured to the lower end of the plug 228 is a plate 230 operable to be brought into engagement with a coupling I65. The plate 230 is provided with indentations 23I for accommodation of embossings I10 on the coupling I65 in order that rotations of the plate 230 may be transmitted to the coupling I65 when the plate 230 is brought into engagement with the coupling I65. A cap 232 is secured by suitable fastening means 233 to the top of the shaft 225 and a bar 234 is secured to the cap 232 to extend diametrically across the recess 93 and into the keyways 95-95. A disc I I9 is secured by rivets I20 or other suitable fastening means to the top of the bar 234.

When it is desired to rotate the coupling I65 by means of the type D control knob device 2I9 the operator may press the disc 9 inwardly of the knob 68 to force the shaft 225 longitudinally of the bushing 22I and against the action of the spring 221 and to bring the plate 230 into engagement with the coupling I65. While holding the parts in this position the operator may turn the knob 68 to cause the coupling I65 to turn. Release of the pressure on the disc H9 will result in the retraction of the plate 230 from the coupling I65 by the upward pressure of the spring 221.

Figs. 13, 14, 15 and 16 show a coupling 235 that may be used in place of the coupling I65 above described. Figs. 17 and 18 show a plate 236 that may be used in place of the plate I33 above described. The coupling 235 and the plate 236 shown in Figs. 13 to 18, inclusive, are drawn on enlarged scale relative to illustrations of the coupling and plate members in other figures of the drawings.

The coupling 235 comprises a body 231, an apertured end plate 238 and a T-shaped plunger 239. The body 231 has an apertured end portion 240 from which two walls 2 and 242 extend in spaced parallel relation to form in cooperation with the end portion 240 a recess 243 in which the cross-arm portion 244 of the T-shaped plunger 239 may be accommodated. The free end portions of the walls 241 and 242 are arranged to form a rest for the end plate 238 which serves as a closure for one end of the recess 243. The walls-241 and 242 may be drilled and tapped at 245 to receive mounting screws 246 or other suitable means for holding the end plate 238 in place. The outer face of the end plate 238 is provided with spaced embossings 241 and the end plate 238 may have a central aperture 248 provided therein and opening into a recess 249 formed in the inner face of the end plate 238. The T-shaped plunger 239 has a tubular body portion 250 extending through the apertured end portion 240 of the body 231 and suitable for mounting on a shaft not shown in these figures but which may be the shaft I66 shown in Figs. 8 and 9 or any other shaft on which the coupling 235 is to be mounted. The cross-arm portion 244 of the T-shaped plunger 239 is recessed at 25l to receive a washer 252 and one end of a spring 253, the other end of the spring 253 being disposed in the recess 249 in the inner face of the end plate 238. When the end plate 236 is applied to the body 231 and against the spring 253 the T-shaped plunger 239 as shown in Fig. 14 is urged longitudinally of the body 231 and so that the cross-arm portion 244 of the T-shaped plunger 239 is against the inner surface of the end portion 240 of the body 231. T-shaped plunger 239 is secured to a shaft which is not longitudinally movable and pressure is applied to the outer face of the end plate 236 the body 231 will be moved relative to the T-shaped plun er 239 and lon itudinally thereof against the action of the spring 253.

The plate 236 shown in Figs. 17 and 18 comprises a plate portion 254 and a stem portion 255. The outer face 256 of the plate portion 254 is provided with a plurality of indentations 251. The indentations 251 are relatively closely spaced and arran ed in a circle concentric with the stem portion 255. The indentations 251 are arranged so that any two diametrically disposed indentations 251 may, receive the embossings 241 on the end plate 238 of the coupling 235. When the plate 236 is suitably connected to a rotatable member in a control knob device and the body portion 256 of the T-shaped plunger 239 in the coupling 235 is connected to a rotatable shaft the coupling 235 and the plate 236 may be used to provide a mechanical connection between the control knob device and the shaft. To drivingly connect the parts the plate 236 is brought into engagement with end plate 238 and so that the embossings 241 are engaged in the indentations 251.

It will be seen that the casing 29 is provided with removable control panels, control knob devices for operating electriccontrol devices in the casing20 are supported on the removable control panels and that when the removable control panels are removed from the casing 20 the control knob devices still remain on the removable control panels and come away with the panels. Also that the control knob devices provided on the removable control panels are constructed and arranged so that the knob membersin the control knob devices may be freely turned without turning shafts in the casing 20 unless the control knob devices are intentionally operated to bringparts of the control knob devices into such condition that the shafts in the casing 20 will be operated when the knob members of the control knob devices are turned. The couplings employed in cooperation with the control knob devices are constructed so that whe When the the removable control panel is being applied to the casing 20 one part of the coupling will move longitudinally relative to another part connected to a shaft in the casing 2|] to compensate for inaccurate spacing of the shaft relative to the normal position of the removable control panel.

What is claimed is: V

1. An electrical control device comprising a fixed body, a bearing supported in said body, a control knob rotatably supported on said bearing, a bushing rotatably supported in said bearing and secured to said control knob, a rotatable shaft extending through said bushing and in rotatable driving connection with said bushing, a return spring for said shaft, a driving connection between said shaft and said bushing, said shaft being operable longitudinally within said bushing and against the action of said spring and a crank supported in said control knob and operable to longitudinally move said shaft in said bushing.

2. A control knob device comprising a body, a tubular bearing supported in said body and extending beyond said body, a control knob rotatably supported on said bearing, a bushing extending into said bearing and rotatable relative to said bearing and secured to said control knob, a shaft extending longitudinally through said bushing, said shaft being longitudinally movable in said bushing and rotatable with said bushing, a spring to restore said shaft to normal position, a crank pivotally mounted on said control knob and operable to move said shaft longitudinally in one direction in said bushing, a plate and a cup-shaped member mechanically connected to said shaft and a clutch surface on said plate.

3. A control knob device comprising, in com bination, a body, a tubular bearing supported in said body and extending beyond said body, a control knob rotatably supported on said bearing, a bushing extending into said bearing and rotatable in said bearing and secured to said control knob, a shaft extending through said bushing and movable longitudinally in said bushing and operable to be rotated by said bushing, a spring to restore said shaft to normal position, a crank pivotally mounted on said control knob and operable to move said shaft longitudinally and against the action of said spring, a plate and a cupshaped member mechanically connected to said shaft, a clutch surface formed on said plate, a coupling operable to extend into said cup-shaped member, an end plate on said coupling operable to be engaged by said clutch surface, a brake member engageable with said cup-shaped memher and a support for said brake member.

EDWARD D. MEAD. ORWAR S. A. MESCH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Lorenz Era-9--..-- Mar. 14, 1944 

